A variety of push-button actuated dispensing valves for dispensing liquids from a relatively large capacity container are known in the art. Where the dispensing valve or tap is used with a flexible wall container, it is not necessary for the container to be vented in any way because no pressure differential is created upon the emptying of the container through the tap.
However, with a rigid container, a system must be provided for equalizing the pressure differential created as contents of the rigid wall container are extracted. Such a vent may be remote from the dispensing valve and may merely comprise a capped opening in an upper wall of the container which, when uncapped, permits ingress of air into the container volume as the liquid contents of the container are being dispensed. Also known in the prior art are self-venting valves eliminating the need for a separate, remote vent opening in the container. Those with knowledge of the dispensing art will recognize with the discussion below how embodiments of the present invention not only differ, but how embodiments of the present invention provide for a much more functional liquid dispenser.
It would be desirable to have a low cost, easy to assemble, reliably operating, mess-free dispensing valve for a rigid container, which will work well with both viscous and low viscosity liquids. It is also desirable to have a dispensing valve which provides an automatic shut off function to prevent inadvertent dispensing. It is desirable to provide a liquid dispenser which does not require a separate input for air on the container, which requires more manufacturing costs.